A call to end the epidemic of adolescent E-cigarette use

Adolescent vaping behaviours: Exploring the dynamics of a social contagion model

Vaping, or the use of electronic cigarettes (e-cigarettes), is an ongoing issue for public health. The rapid increase in e-cigarette usage, particularly among adolescents, has often been referred to as an epidemic. Drawing upon this epidemiological analogy between vaping and infectious diseases as a theoretical framework, we present a deterministic compartmental model of adolescent e-cigarette smoking which accounts for social influences on initiation, relapse, and cessation behaviours. We use results from a sensitivity analysis of the model's parameters on various response variables to identify key influences on system dynamics and simplify the model into one that can be analysed more thoroughly. We identify a single feasible endemic equilibrium for the proportion of smokers that decreases as social influence on cessation increases. Through steady state and stability analyses, as well as simulations of the model, we conclude that social influences from and on temporary quitters are not important in overall model dynamics, and that social influences from permanent quitters can have a significant impact on long-term system dynamics. In particular, we show that social influence on cessation can induce persistent recurrent smoking outbreaks.

Awareness and perceived behaviour changes following the New York state vaping flavour ban, 2021-2022

SIGNIFICANCE

Despite an electronic cigarette (e-cigarette) flavour ban in New York (NY) since May 2020, most youth who vape continue to report vaping restricted flavours. This study aims to examine youth awareness and perceived behaviour change associated with the NY vaping flavour ban.

METHODS

NY cross-sectional data from 2021 and 2022 ITC Youth Survey were combined and analysed (N=1014). Weighted analyses were used to describe awareness and understanding of the e-cigarette flavour ban, as well as changes in tobacco use behaviour.

RESULTS

Only 0.9% (n=8) of NY youth understood the flavour ban, in that they were both aware of the flavour ban in all stores and accurately reported that all non-tobacco flavours were banned. Awareness and understanding of the flavour ban differed by vaping status (p<0.01): respondents who had vaped in the past 12 months or 30 days were more likely (adjusted OR (aOR)=2.15, 95% CI 1.34, 3.45; aOR=2.07, 95% CI 1.17, 3.64, respectively) to be aware of the flavour ban but misunderstand the stores or flavours included. Of the majority of youth who reported awareness of a flavour ban and vaped (n=122) or smoked (n=78) in the past 12 months reported no changes in behaviour (64.0% and 69.7%, respectively).

CONCLUSIONS

Less than one-third of NY youth, regardless of vaping status, reported that an e-cigarette flavour ban was present where they live. Further, most youth who were aware of the ban misunderstood which flavours were restricted and/or that the ban applied to all stores that sold e-cigarettes. Increased enforcement and educational efforts could improve awareness and understanding of the NY e-cigarette flavour ban.

Applying Social Network Theory to Vaping in High School: Implications for Person-Centered Intervention

BACKGROUND

Peer influence on risky behavior is particularly potent in adolescence and varies by gender. Smoking prevention programs focused on peer-group leaders have shown great promise, and a social influence model has proven effective in understanding adult smoking networks but has not been applied to adolescent vaping until 2023. This work aims to apply a social influence model to analyze vaping by gender in a high school network.

METHODS

A high school's student body was emailed an online survey asking for gender, age, grade level, vape status, and the names of three friends. Custom Java and MATLAB scripts were written to create a directed graph, compute centrality measures, and perform Fisher's exact tests to compare centrality measures by demographic variables and vape status.

RESULTS

Of 192 students in the school, 102 students responded. Students who vape were in closer-knit friend groups than students who do not vape (p < .05). Compared to males who vape, females who vape had more social ties to other students who vape, exhibiting greater homophily (p < .01). Compared to females who do not vape, females who vape were in closer-knit friend groups (p < .05) and had more ties to other students who vape (p < .01).

CONCLUSION

Differences in vaping by social connectedness and gender necessitate school and state policies incorporating the social aspect of vaping in public health initiatives. Large-scale research should determine if trends can be generalized across student bodies, and more granular studies should investigate differences in motivations and social influence by demographic variables to individualize cessation strategies.

Disparities in E-Cigarette Harm and Addiction Perceptions Among Adolescents in the United States: a Systematic Review of the Literature

BACKGROUND

Health disparities associated with e-cigarette use are increasingly apparent among US adolescents. Perceptions of e-cigarette harm and addiction play an important role in understanding adolescents' e-cigarette use behavior. The objective of this systematic review is to examine racial/ethnic and socio-economic disparities in e-cigarette harm and addiction perceptions among US adolescents.

METHODS

We searched five databases to identify cross-sectional or longitudinal studies that focused on adolescents (≤ 18 years of age) who were ever, current, or never e-cigarettes users; we then examined how race/ethnicity and/or socio-economic status (SES) impacted e-cigarette harm and/or addiction perceptions. Two co-authors independently identified relevant studies, extracted data, and assessed the risk of bias.

RESULTS

Adhering to PRISMA guidelines, eight of 226 identified studies met the inclusion criteria. These eight studies examined either perceptions regarding absolute e-cigarette harm and/or addiction (i.e., assessing perception of only e-cigarette) or relative e-cigarette harm and/or addiction (i.e., comparative perceptions to traditional cigarettes) by race and ethnicity. Two of the eight studies assessed absolute harm and/or addiction perceptions of e-cigarettes by SES. Our results indicate that, compared to all other racial/ethnic groups, relative e-cigarette harm and addiction perceptions were lower among Non-Hispanic White adolescents; however, absolute e-cigarette harm perception was higher among these groups. No clear patterns of racial/ethnic differences in absolute e-cigarette addiction perceptions and SES differences in absolute e-cigarette harm perceptions were reported.

CONCLUSION

More research is needed to explicitly assess perceptions of e-cigarette harm and addiction among US adolescents by race/ethnicity and SES to develop subgroup appropriate public health messaging.

Predictors of Adolescents' Transition Through the Stages of Change for Quitting E-Cigarettes: Findings From the Population Assessment of Tobacco and Health Study

PURPOSE

To identify predictive factors associated with US adolescents' transition through the stages of change for potentially quitting e-cigarettes using the Trans-theoretical model of behavior change.

DESIGN

Prospective cohort study.

SETTING

United States.

SUBJECTS

We utilized data from adolescents (12-17 years) in Wave 3 of the Population Assessment of Tobacco and Health study who used e-cigarettes exclusively over the past 30 days (n = 177) and were followed up with in Wave 4.

MEASURES

Outcome variables were 3 transition categories: those who remained stagnant, those who progressed, and those who regressed in their stage of quitting e-cigarettes. Predictor variables were socio-demographics, e-cigarette harm perception, e-cigarette use at home or by important people, social norms, e-cigarette and anti-tobacco advertisements, and e-cigarette health warnings.

ANALYSIS

Weighted-adjusted multinomial regression analysis was performed to determine the association between predictor and outcome variables.

RESULTS

From Wave 3 to Wave 4, 19% of adolescents remained stagnant; 73.3% progressed; and 7.7% regressed. Adolescents were less likely to progress in their stage of change if they perceived nicotine in e-cigarettes to be "not at all/slightly harmful" (AOR = .26 [95% CI: .25, .27], P < .001); reported important people's use of e-cigarettes (AOR = .18 [95% CI: .05, .65, P = .009); and "rarely" noticed e-cigarette health warnings (AOR = .28 [95% CI: .08, .98, P = .054).

CONCLUSION

Intervention efforts must target specific predictive factors that may help adolescents quit e-cigarettes.

Multiple Tobacco Product Use Among Youth E-Cigarette Users: National Youth Tobacco Survey, 2020

PURPOSE

Limited information exists on multiple tobacco product use, particularly among youth. This study assessed the prevalence of current youth use of e-cigarettes with other tobacco products and their associated characteristics using 2020 National Youth Tobacco Survey data.

METHODS

Prevalence estimates were calculated for current e-cigarette users, by multiple tobacco product use status and product combination. Demographic characteristics, e-cigarette use behaviors, age at first combustible tobacco use, and tobacco dependence symptoms were compared between current users of both e-cigarettes and combustible tobacco (dual users) and current exclusive e-cigarette users.

RESULTS

In 2020, 61.1% of all current e-cigarette users reported exclusive e-cigarette use, and 38.9% used e-cigarettes with other tobacco products. Among those who used e-cigarettes with other tobacco products, 85.0% used combustible tobacco, with cigarettes being the most commonly used other tobacco product. Compared with current exclusive e-cigarette users, higher proportions of dual users reported the following: frequent e-cigarette use; obtaining e-cigarettes from gas stations, persons other than a family member/friend, vape shops, or the internet; and having any tobacco dependence symptoms. Among dual users, 31.2% reported first combustible product use after e-cigarette initiation, and 34.3% reported first combustible product use prior to e-cigarette initiation.

DISCUSSION

Approximately four in 10 youth current e-cigarette users reported using multiple tobacco products, with a majority using combustible tobacco. Frequent e-cigarette use and tobacco dependence symptoms were more prevalent among dual users of e-cigarettes and combustible tobacco.

Vaping Among Adolescents: An Overview of E-Cigarette Use in Middle and High School Students in India

E-cigarette use among middle and high school students has become a growing public health concern in recent years. The prevalence of e-cigarette use among adolescents has increased dramatically, and there are serious health risks associated with this behavior. This review article provides an overview of e-cigarette use in middle and high school students, including the prevalence of use, contributing factors, health effects, policies and regulations surrounding e-cigarette use in schools, and interventions for preventing e-cigarette use in adolescents. The article highlights the need for effective prevention and cessation programs, increased public awareness about the risks of e-cigarette use, and stronger regulations on e-cigarette products. Addressing e-cigarette use among youth is critical for protecting the health and well-being of future generations, and it is important for parents, educators, healthcare providers, and policymakers to work together to prevent and reduce e-cigarette use among adolescents and promote healthy behaviors.

User-generated content and influencer marketing involving e-cigarettes on social media: a scoping review and content analysis of YouTube and Instagram

BACKGROUND

Evidence suggests that experimentation with e-cigarettes among young people is increasing. Social media is widely used by young people with user-generated content and influencer marketing particularly influential in promoting products. This paper documents a snapshot of online user-generated content and influencer marketing related to e-cigarettes on YouTube and Instagram.

METHODS

Scoping review of relevant e-cigarette-related content on two social media platforms popular with youths, YouTube and Instagram, between June and August 2021. Content analysis was undertaken to examine text, audio, and video content, recording age restrictions, health warnings, page characteristics, and post characteristics. Narrative post content was coded using a coding frame that was developed inductively in response to emergent categories.

RESULTS

Vaping was portrayed positively on social media; of the posts analysed, 86.5% (n = 90 of 104) of Instagram posts and 66.0% (n = 64 of 97) of YouTube videos. Warnings about age restrictions and health (e.g., nicotine addiction/toxicity) did not feature in the majority of posts; 43.3% (n = 42) of YouTube videos (n = 42) contained an age warning compared to 20.2% of Instagram posts (n = 21). While 25.8% (n = 25) of YouTube videos and 21.2% of Instagram (n = 22) posts contained a health warning.

CONCLUSION

Of concern is the fact that the vast majority of YouTube and Instagram content about e-cigarettes promoted their use, and typically the content does not contain age and/or health warnings. These findings may highlight a priority for governmental policy to restrict the ability of marketers to reach youths with social media content promoting e-cigarettes.

Factors Associated With E-Cigarette Quitting Behavior Among Adolescents in the United States: A Prospective Observational Study

PURPOSE

This prospective observational study examined the association of socioecological factors with quitting behavior among US adolescents who exclusively use electronic cigarettes (e-cigarettes).

METHODS

We used data from past 30-day adolescent exclusive e-cigarette users (n = 243) participating in Wave 3 of the Population Assessment of Tobacco and Health study, who were then followed-up with approximately 12 months later for Wave 4. Weighted unadjusted and adjusted multivariate logistic regression models and structural equation modeling were performed to analyze the data.

RESULTS

Adolescents were significantly less likely to quit e-cigarettes if they perceived that nicotine in e-cigarettes was "slightly/somewhat harmful" to health (adjusted odds ratio [aOR] = 0.38; 95% confidence interval [CI]: 0.16-0.90, p = .02). Similarly, adolescents who reported that someone else in their home owned an e-cigarette (aOR = 0.43 [95% CI: 0.19-0.94], p = .03) or important people in their life used e-cigarettes (aOR = 0.45 [95% CI: 0.21-0.95], p = .03) were significantly less likely to quit e-cigarettes. The structural equation modeling showed a direct significant relationship of individual-level (b = 0.206, p = .02) and interpersonal-level factors (b = 0.170, p = .04) with e-cigarette quitting behavior.

DISCUSSION

Our findings suggest that individual-level (harm perception) and interpersonal-level (e-cigarette use at home and by important people) factors may play a significant role in e-cigarette quitting behavior among US adolescents.

Multiple Tobacco Product Use among Adolescents with Asthma in Korea

Few studies have examined the use of multiple tobacco products among adolescents with asthma. The purpose of this study was to examine multiple tobacco product use and smoking behaviors. In this study, data from the Korea Youth Risk Behavior Web-based Survey (KYRBWS) were used, and 57,303 samples from 400 middle schools and 400 high schools in Korea were classified as study participants. Statistical analysis was performed with a complex sample design, using frequency analysis, chi-square test, and multiple logistic regression analysis. Adolescents with asthma had a higher current smoking rate for combustible cigarettes (CC), e-cigarettes (EC), and heated tobacco products (HTPs) than those without asthma (p < 0.001). The rates of dual use (using two types of tobacco; CC + EC or CC + HTPs or EC + HTPs; OR = 2.62, 95% CI: 1.626−4.240, R2 = 26.8%) and triple use (using three types of tobacco; CC + EC + HTPs; OR = 2.61, 95% CI: 1.678−4.065, R2 = 34.9%) were higher in adolescents with asthma than those without asthma, after adjusting for confounders. The smoking rate of new types of tobacco among adolescents with asthma is on the rise. Therefore, the calculation of basic data related to new tobacco smoking among adolescents is essential for establishing a continuous monitoring system to alleviate the burden of disease on national health.

Sex and age differences in approach behavior toward a port that delivers nicotine vapor

The goal of our laboratory is to study the mechanisms that promote nicotine use, particularly in vulnerable populations. To more closely mimic human use patterns, the present study employed nicotine vapor methods involving passive exposure for 14 days in adolescent and adult female and male rats. Age and sex differences in approach behavior (nosepokes) were assessed in a port that delivered nicotine plumes on Day 1 and 14 of our exposure regimen. Controls received ambient air in exposure chambers. After the final session, rats received a nicotinic receptor antagonist to precipitate withdrawal. Then, physical signs, anxiety-like behavior, and plasma levels of cotinine (a nicotine metabolite) were assessed. Over time, females displayed a larger increase in approach behavior to the nicotine port than males, an effect that was larger in adolescents. Nosepoke responses in adolescent females were correlated with anxiety-like behavior, but not physical signs of withdrawal. Adolescents gained more weight than adults regardless of treatment, and the weight gain was larger in male adolescents. Female adolescents also displayed the highest levels of cotinine than all other groups. These findings suggest that nicotine vapor produces greater motivational effects in adolescent females as compared to their adult and male counterparts.

Physical and mental health outcomes associated with adolescent E-cigarette use

INTRODUCTION

Use of electronic cigarettes (e-cigarette) and other electronic nicotine delivery systems (ENDS) among adolescents has increased dramatically, creating a need for research to examine the consequences of e-cigarette use on adolescent health. Given the emergent state of the research literature, this integrative review sought to summarize what is currently known about the physical and mental health outcomes associated with e-cigarette use in an adolescent population, and to identify directions for future research.

METHOD

The methodology for this integrative review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A methodical search was conducted in February 2020 in PubMed, CINAHL, and Web of Science databases. To be eligible for inclusion, studies had to address e-cigarette use, have samples that were between 13 and 24 years of age, be published in a peer-reviewed journal, and examine health outcomes associated with e-cigarette use. After the screening process, 18 studies were included.

RESULTS

Physical health outcomes associated with e-cigarette use included oral health and respiratory problems as well as nicotine dependence. Mental health outcomes included depression and suicidal ideation. In studies that compared e-cigarette use to conventional cigarette use and non-use, e-cigarettes tended to be associated with more problems than non-use, but fewer problems than conventional cigarette use. Dual use, that is, use of both conventional cigarettes and e-cigarettes, was associated with the greatest harm.

CONCLUSION

Although somewhat less harmful than conventional cigarettes, e-cigarette use is related to a variety of negative physical and mental health outcomes among adolescent users.

E-cigarette device type and combustible tobacco use: Results from a pooled analysis of 10,482 youth

INTRODUCTION

To understand whether using a certain e-cigarette device is more strongly associated with risk of combustible tobacco use among youth.

METHODS

We conducted multivariable logistic regression analyses using cross-sectional data from 4 samples of youth in Connecticut and California (N = 10,482; ages 13-24), separately for each study using the total sample and the sample of past-month e-cigarette users, to understand the association between e-cigarette device type and past-month combustible tobacco use, while controlling for age, sex, race/ethnicity, socioeconomic status, school, and past-month marijuana use. Then, we conducted meta-analyses to calculate pooled associations for adolescents, young adults, and all individuals combined.

RESULTS

Among the total sample, combustible tobacco use was associated with any e-cigarette device use (vs. no e-cigarette use) in the pooled analysis across all studies. Among past-month e-cigarette users, combustible tobacco use across all studies was 15.8%- 61.5%. Pooled associations among past-month e-cigarette users showed that using disposable devices (vs. pods; AOR=2.83, 95% CI: 1.73-4.61) and multiple devices most frequently (vs. pods; AOR=2.13, 95% CI: 1.16-3.90) was associated with greater odds of combustible tobacco use. Pooled associations also found that using multiple devices (vs. a single device) in the past month was associated with greater odds of combustible tobacco use (AOR 2.33, 95% CI: 1.74, 3.14).

DISCUSSION

Using disposable e-cigarettes and multiple devices is associated with greater likelihood of combustible tobacco use among e-cigarette using youth. Future research should elucidate the trajectory of e-cigarette device used and combustible tobacco use among youth to inform prevention and product regulation.

Influence of Flavors and Nicotine Concentration on Nicotine Dependence in Adolescent and Young Adult E-Cigarette Users

Objective: The objective of this study is to examine the relationships between e-cigarette flavors, nicotine concentration, and their interaction on measures of nicotine dependence.Methods: Survey data are drawn from a cross-sectional convenience sample of past 30-day e-cigarette users aged 15 to 24 years (N = 2037) collected between October 2020 and November 2020. Participants were asked to provide information about the e-cigarette products they used most regularly. Only those with available information on flavors (fruit, mint, menthol/ice, and tobacco), nicotine concentration (0-2.9%, 3-4.9%, and 5% or greater), and time to first vape after waking (within 30 minutes, greater than 30 minutes) were included in analyses (N = 1430). Generalized linear regression models were used with log link and binary distribution to assess the relationship between flavors, nicotine concentration, and nicotine dependence. Effect modification by nicotine concentration was assessed using an interaction term for flavors by nicotine concentration. Models were adjusted for age, race/ethnicity, gender, and financial situation.Findings: Fruit, mint, and menthol flavor user groups had a very similar dose-response relationship between nicotine concentration and prevalence of vaping within 30 minutes. These groups showed that the prevalence of vaping within 30 minutes gradually increased as nicotine concentration increased. Meanwhile, tobacco flavor user groups demonstrated a decrease in prevalence of vaping within 30 minutes, as nicotine concentration increased.Conclusion: Results highlight the need for understanding how e-cigarette product characteristics like flavors and nicotine concentration can facilitate nicotine dependence to e-cigarettes. Findings suggest that comprehensive e-cigarette product regulation of all flavors and reducing nicotine concentration will help to reduce the risk for nicotine dependence among young people.

Factors Associated with E-Cigarette Quit Intention Among Adolescents in the United States

Background: Given increasing use of e-cigarettes among adolescents in the United States and its potential for nicotine addiction, encouraging adolescents to quit using these products has become a public health priority. This study examined factors at various socio-ecological levels associated with e-cigarette quit intention (pre-contemplation, contemplation, or preparation) using the Stages of Change of the Trans-theoretical Model among the U.S. adolescents. Methods: We used cross-sectional data from the past 30-day adolescent exclusive e-cigarette users participating in Wave 4 of the Population Assessment of Tobacco and Health study (n = 349). Weighted adjusted multinomial logistic regression models were used to analyze the data. Results: Compared to pre-contemplators and contemplators, preparators were more likely to believe that nicotine in e-cigarettes was "very/extremely harmful" (vs. "not at all harmful") to health (p < 0.001) and people cause a "lot of harm" (vs. "no harm") to themselves when they use e-cigarettes (p < 0.001). In comparison to pre-contemplators, contemplators and preparators were more likely to report that their parents/guardians talked with them about not using e-cigarettes than those whose parents/guardians did not talk with them (p < 0.001). Additionally, contemplators and preparators were also more likely to report that they "often/very often" (vs. never) noticed health warnings on e-cigarette packages (p < 0.001). Conclusion: Our findings suggest that harm perception, influence of family, and e-cigarette health warnings are some of the important factors associated with the stages of change for intention to quit among adolescent e-cigarette users. This study will help public health practitioners and researchers design multi-level e-cigarette cessation interventions for adolescents.

Evaluation of a virtual reality E-cigarette prevention game for adolescents

OBJECTIVE

To test preliminary efficacy and acceptability of Invite Only VR: A Vaping Prevention Game (Invite Only VR), an electronic cigarette (e-cigarette) prevention game that uses virtual reality (VR) hardware.

METHODS

285 adolescents (146 boys; ages 11-14; M = 12.45 years; SD = 0.57) were enrolled in this non-equivalent control groups design through their middle school. Participants who played Invite Only VR for 1.5 h were compared to treatment as usual at 4 timepoints: baseline, post gameplay, 3 and 6 months. Evidence of the efficacy of the game to influence e-cigarette use, e-cigarette knowledge, nicotine addiction knowledge, perceived addictiveness of e-cigarettes, perceived likelihood of using e-cigarettes, perceptions of harm, self-efficacy to refuse, social approval of e-cigarettes, and e-cigarette social perceptions was assessed using mixed between-within subjects ANOVAS. Intervention acceptability was indicated by measures of gameplay experience/satisfaction, VR experience, and perceived responsibility for game-based decisions.

RESULTS

From baseline to 6 months, Invite Only VR players improved in e-cigarette knowledge, nicotine addiction knowledge, perceived addictiveness of e-cigarettes, perceptions of harm, and social perceptions about e-cigarette use compared to the control group. No significant changes were observed for the other dependent variables, including e-cigarette use. Ratings of gameplay experience and satisfaction, VR experience, and game-based decisions were high.

CONCLUSIONS

Invite Only VR may help players develop knowledge about e-cigarettes and nicotine addiction, as well as encourage the development of healthy harm and social perceptions regarding e-cigarette use that persist 6 months beyond gameplay. Adolescents' satisfaction with the VR gameplay indicates preliminary intervention acceptability.

Radiologic Review With Pathology Correlation of E-Cigarette or Vaping Product Use-associated Lung Injury

More than 2000 cases of vaping-associated lung injury have been reported in a recent outbreak, including >40 deaths. Although chest imaging is integral in the evaluation of these patients and is often abnormal, the spectrum of findings and the role of imaging in the diagnosis are not widely appreciated. The aim of this review is to highlight the imaging findings of vaping-associated lung injury. Basilar-predominant ground-glass opacities and/or consolidations, often with areas of subpleural or lobular sparing, are the most common pattern, and many other patterns are known to occur. Radiologists are encouraged to become familiar with the different imaging patterns of vaping-associated lung injury. The diagnosis should be considered in patients who have vaped within 90 days of onset of symptoms and present with bilateral lung opacities.

Impact of e-Liquid Composition, Coil Temperature, and Puff Topography on the Aerosol Chemistry of Electronic Cigarettes

E-cigarette aerosol is a complex mixture of gases and particles with a composition that is dependent on the e-liquid formulation, puffing regimen, and device operational parameters. This work investigated mainstream aerosols from a third generation device, as a function of coil temperature (315-510 °F, or 157-266 °C), puff duration (2-4 s), and the ratio of propylene glycol (PG) to vegetable glycerin (VG) in e-liquid (100:0-0:100). Targeted and untargeted analyses using liquid chromatography high-resolution mass spectrometry, gas chromatography, in situ chemical ionization mass spectrometry, and gravimetry were used for chemical characterizations. PG and VG were found to be the major constituents (>99%) in both phases of the aerosol. Most e-cigarette components were observed to be volatile or semivolatile under the conditions tested. PG was found almost entirely in the gas phase, while VG had a sizable particle component. Nicotine was only observed in the particle phase. The production of aerosol mass and carbonyl degradation products dramatically increased with higher coil temperature and puff duration, but decreased with increasing VG fraction in the e-liquid. An exception is acrolein, which increased with increasing VG. The formation of carbonyls was dominated by the heat-induced dehydration mechanism in the temperature range studied, yet radical reactions also played an important role. The findings from this study identified open questions regarding both pathways. The vaping process consumed PG significantly faster than VG under all tested conditions, suggesting that e-liquids become more enriched in VG and the exposure to acrolein significantly increases as vaping continues. It can be estimated that a 30:70 initial ratio of PG:VG in the e-liquid becomes almost entirely VG when 60-70% of e-liquid remains during the vaping process at 375 °F (191 °C). This work underscores the need for further research on the puffing lifecycle of e-cigarettes.

Rethink Vape: Development and evaluation of a risk communication campaign to prevent youth E-cigarette use

INTRODUCTION

E-cigarettes are now the most common form of tobacco use among adolescents, and use is associated with increased risk of initiation of cigarette smoking. This project used a community-engaged research process to develop and pilot a risk communication campaign to prevent youth vaping.

METHOD

The research team worked with a 36-member Teen Advisory Council and a 19-member Expert Panel. Together, the team employed survey (N = 674) and focus group (N = 82) methodologies, and hired a marketing company to partner on development of the campaign. Campaign concepts were developed, eliminated, and/or modified through an iterative process of feedback and refinement. The final campaign included video ads (https://bit.ly/2QMR8gH) a microsite (rethinkvape.org), and social media sites (@rethinkvape). The campaign communicated three messages to teens: what's in the vapor, health risks, and connections to big tobacco. Prior to launch of the campaign, a randomized controlled 2 (time) × 2 (group) online experiment was conducted to evaluate the campaign (N = 268).

RESULTS

Repeated measures mixed analyses of variance indicated that vaping knowledge, perceptions of risk, and anti-vape intentions significantly increased among teens viewing the Rethink Vape Materials compared to their own baseline, while control participants did not change. Following evaluation, the team launched a 6-week online media campaign with a teen-targeted geo-fence radius to deliver 3,838,465 impressions, 770,443 completed video views, and 18,316 clicks in mobile app, Snapchat, YouTube, and Spotify platforms. The majority of placements exceeded industry standards, with mobile pre-roll and Snapchat as top performers.

CONCLUSIONS

The e-cigarette campaign showed promising signs of effectiveness and scalability.

Simultaneous Use of Alcohol and Electronic Nicotine Delivery Systems among College Students: Vaping History, Motivations for Use, and Outcome Expectancies

Introduction: Simultaneous polydrug use of electronic nicotine delivery systems (ENDS) and alcohol among college students is not well understood despite high rates of vaping and alcohol use among this population. The current study examined rates of simultaneous use and compared demographic characteristics, vaping history, motivations for initiating use, and outcome expectancies based on polydrug use status. Methods: An online and paper-and pencil questionnaire was administered to undergraduate students at a university in the northeast of the U.S. Purposive sampling strategies were used and a raffle was offered to incentivize participation. Results: Simultaneous polydrug use was prevalent in the sample of 670 college students, with 55.6% reporting simultaneous and non-simultaneous use, 34.0% reporting simultaneous use only, and 10.4% reporting non-simultaneous use only. An examination of differences based on polydrug use status indicated that students who reported simultaneous and non-simultaneous use were more likely to be males, report vaping daily, and endorse a wide range of motivations for use. Students who engaged in simultaneous use only were more likely to be females, indicate a social contextual-related motivation for initiating use, and had higher scores on appetite control, emotion regulation, and taste sensation outcome expectancies. Students who engaged in non-simultaneous use only were more likely to be nonwhite students and report the lowest expectation of health risks. Conclusions: The findings reveal differences based on simultaneous polydrug use status that can be informative in the development of contextually relevant prevention programming. Future research is needed to further explore simultaneous use of ENDS and alcohol.

Vaping, smartphones, and social media use among young adults: Snapchat is the platform of choice for young adult vapers

BACKGROUND

Tobacco use often begins or stabilizes in young adulthood. Approximately 90% of young adults use social media and over 80% own a smartphone. Retailers of electronic nicotine delivery systems (ENDS) have targeted smartphones and social media with adverting campaigns. Despite evidence of ENDS advertising on social media and smartphones, few studies have examined associations between exposure to vaping advertisements on smartphones, social media use, and ENDS use (i.e., vaping) among young adults.

METHODS

College students aged 18-24 from a large public university (N = 1047) completed online surveys about vaping. The survey measured frequency of vaping advertisement exposure, smartphone use, social media use, and vaping behaviors. Hierarchical logistic regression assessed whether demographics, vaping advertisement exposure, smartphone use, and social media use predicted ever vaping compared to never vaping.

RESULTS

The four most commonly used platforms (used "daily") were Snapchat (80.0%), Instagram (73.4%), YouTube (59.7%), and Facebook (54.3%). Use of Snapchat, Instagram, and Facebook were all significantly associated with higher rates of vaping advertisement exposure via smartphones. Exposure to vaping advertisements on smartphones was associated with ever vaping (AOR: 1.30, 95% CI = 1.05-1.60). Of the social media platforms examined, only Snapchat use frequency was associated with higher odds of ever vaping (AOR: 1.22, 95% CI = 1.10-1.36).

CONCLUSIONS

Exposure to advertisements via smartphones and use of Snapchat were associated with higher rates of vaping for young adults. Social media and smartphone use should be further investigated for young adult impact.

Electronic Cigarette Use Among Youth: Understanding Unique Risks in a Vulnerable Population

PURPOSE OF REVIEW

This review discusses prevalence rates of electronic (e-)cigarette use among youth and factors that likely contribute to their growing popularity among this population. Trends shaping the e-cigarette landscape, the appeal of e-cigarettes among youth, perceptions contributing to the initiation of e-cigarettes, available assessments capturing the usage of and attitudes towards e-cigarettes, and e-cigarette policies and regulations are reviewed.

RECENT FINDINGS

E-cigarette use among this vulnerable group may relate to factors associated with the promotion of social status, individuality, and enjoyment, along with low perceptions of risk and harm. Measures assessing factors unique to e-cigarette use among youth (e.g., individuality) still need to be developed and validated. Effects of existing regulations to limit youth access to e-cigarettes may be limited, and shortcomings of current policy measures are discussed with recommendations.

SUMMARY

The rise of e-cigarette use among youth culminated through a perfect storm of clever marketing targeting youth appeal, innovations in more effective nicotine delivery systems, capitalizing on increased susceptibility of the adolescent brain, and regulatory gaps. Understanding risk and protective factors specific to this vulnerable group, which can be gleaned in part by psychometrically valid assessments, could inform regulatory strategies and prevention programming efforts. Yet, few validated measures exist that assess attitudes, behaviors, and patterns of e-cigarette use that are specific to youth. Ultimately, it is incumbent upon policymakers to create comprehensive regulations that prioritize harm reduction and can evolve in lockstep with the constantly changing e-cigarette product landscape.

Cell invasion, RAGE expression, and inflammation in oral squamous cell carcinoma (OSCC) cells exposed to e-cigarette flavoring

Objective

Electronic cigarettes have given rise to a new, largely unregulated market within the smoking industry. While generally supposed to be less harmful than traditional tobacco smoke, awareness of the biological effects of electronic cigarette liquid is still scarce. Our objective was to determine the impact of electronic cigarette flavoring and nicotine on gingival squamous cell carcinoma invasion, RAGE expression, and the elaboration of pro‐inflammatory molecules.

Methods and Materials

Gingival and tongue squamous cell carcinoma cells were exposed to Red Hot or Green Apple flavored electronic cigarette flavoring with or without nicotine. Immunofluorescence determined RAGE expression. Real‐time cellular invasion was assessed using a RTCA DP instrument. Culture medium was assayed for cytokine secretion.

Results

Compared to controls we observed: increased cell invasion in gingival cells with Red Hot electronic cigarette flavoring and decreased cell invasion with Green Apple; decreased cell invasion in tongue cells treated with Red Hot electronic cigarette flavoring and no differences in invasion with Green Apple; flavor and nicotine dependent increases in RAGE expression; and differential expression of IL‐1α, IL‐8, and MMP‐13.

Conclusion

We conclude that electronic cigarette flavoring and nicotine orchestrate differential regulation of oral squamous cell carcinoma (OSCC) cell invasion and inflammatory effects. This study provides an important initial step in dissecting RAGE‐mediated mechanisms of cancerous invasion and molecular avenues employed by OSCC.

Research on Youth and Young Adult Tobacco Use, 2013-2018, From the Food and Drug Administration-National Institutes of Health Tobacco Centers of Regulatory Science

The Tobacco Regulatory Science Program is a collaborative research effort between the National Institutes of Health (NIH) and the Food and Drug Administration (FDA). In 2013, the NIH funded 14 Tobacco Centers of Regulatory Science (TCORS), which serve as partners in establishing research, training, and professional development programs to guide FDA. Each of the fourteen TCORS, and two other NIH-funded research programs, the Center for the Evaluation of Nicotine in Cigarettes (CENIC) and the Consortium on Methods Evaluating Tobacco (COMET), pursued specific research themes relevant to FDA's priorities. A key mandate for FDA is to reduce tobacco use among young people. This article is a review of the peer-reviewed research, including published and in-press manuscripts, from the TCORS, CENIC, and COMET, which provides specific data or other findings on youth (ages 10-18 years) and/or young adults (ages 18-34 years), from 2013 to 2018. Citations of all TCORS, CENIC, and COMET articles from September 2013 to December 2017 were collected by the TCORS coordinating center, the Center for Evaluation and Coordination of Training and Research. Additional citations up to April 30, 2018 were requested from the principal investigators. A scoring rubric was developed and implemented to assess study type, primary theme, and FDA priority area addressed by each article. The major subareas and findings from each priority area are presented. There were 766 articles in total, with 258 (34%) focusing on youth and/or young adults. Findings relevant to FDA from this review concern impact analysis, toxicity, health effects, addiction, marketing influences, communications, and behavior.

IMPLICATIONS

The Tobacco Centers of Regulatory Science, CENIC, and COMET have had a high output of scientific articles since 2013. These Centers are unique in that the FDA supports science specifically to guide future regulatory actions. The 258 articles that have focused on youth and/or young adults are providing data for regulatory actions by the FDA related to the key priority areas such as the addictiveness of non-cigarette products, the effects of exposure to electronic cigarette marketing on initiation and cessation, and the impact of flavored products on youth and young adult tobacco use. Future regulations to reduce tobacco use will be guided by the cumulative evidence. These Centers are one innovative mechanism to promote important outcomes to advance tobacco regulatory science.

Exposure to the Tobacco Power Wall Increases Adolescents' Willingness to Use E-cigarettes in the Future

INTRODUCTION

Adolescents' e-cigarette use is now more prevalent than their combustible cigarette use. Youth are exposed to e-cigarette advertising at retail point-of-sale (POS) locations via the tobacco power wall (TPW), but no studies have assessed whether exposure to the TPW influences susceptibility to future e-cigarette use.

METHODS

The study was conducted in the RAND Store Lab (RSL), a life-sized replica of a convenience store developed to experimentally evaluate how POS advertising influences tobacco use risk under simulated shopping conditions. In a between-subjects experiment, 160 adolescents (M age = 13.82; 53% female, 56% white) were randomized to shop in the RSL under one of two conditions: (1) TPW located behind the cashier (n = 80); or (2) TPW hidden behind an opaque wall (n = 80). Youths rated willingness to use e-cigarettes ("If one of your best friends were to offer you an e-cigarette, would you try it?"; 1 = definitely not, 10 = definitely yes) before and after exposure. Linear regression assessed differences in pre-post changes in willingness to use across conditions.

RESULTS

Ever-use of e-cigarettes was 5%; use of cigarettes was 8%; use of both e-cigarettes and cigarettes was 4%. There were no differences between TPW conditions on these or other baseline variables (eg, age, gender). Compared to the hidden condition, TPW exposure was associated with greater increases in willingness to use e-cigarettes in the future (B = 1.15, standard error [SE] = 0.50, p = .02).

CONCLUSIONS

Efforts to regulate visibility of the TPW at POS may help to reduce youths' susceptibility to initiating e-cigarettes as well as conventional tobacco products like cigarettes.

IMPLICATIONS

Past work suggests that exposure to the TPW in common retail settings, like convenience stores, may increase adolescents' susceptibility to smoking cigarettes. This experimental study builds upon prior research to show that exposure to the TPW at retail POS similarly increases adolescents' willingness to use e-cigarettes in the future. Efforts to regulate the visibility of the TPW in retail settings may help to reduce youths' susceptibility to initiating nicotine and tobacco products, including e-cigarettes.

Disentangling Within- and Between-Person Effects of Shared Risk Factors on E-cigarette and Cigarette Use Trajectories From Late Adolescence to Young Adulthood

BACKGROUND

Longitudinal studies report associations between use of electronic cigarettes (ECs) and cigarettes over time among young people, but do not distinguish within- from between-person effects, which complicates interpretation of findings. Further, the role of shared risk factors, such as substance use and mental health, in explaining longitudinal associations between EC and cigarette use remains unclear. This study used within- and between-person analyses to assess longitudinal associations between youths' EC and cigarette use and shared risk factors.

METHODS

Between 2015 and 2017, 2039 youths completed three Web-based surveys, allowing us to model EC and cigarette use from ages 16 to 20. Auto-regressive latent growth models with structured residuals (ALT-SR) examined both between-person and within-person associations between past-month frequency of EC use, cigarette use, and third variables (alcohol and marijuana use, mental health symptoms) over time.

RESULTS

Models revealed robust reciprocal associations between EC and cigarette use, such that more frequent EC use at one time predicted more frequent cigarette use at the subsequent time, and vice versa. Between-person analyses showed associations between shared risk factors and both EC and cigarette use. However, shared risk factors did not predict frequency of subsequent EC and cigarette use in within-person analyses.

CONCLUSIONS

Findings add to a growing body of research suggesting that EC use among youth is prospectively associated with progression toward greater cigarette use. Shared risk factors may help explain differences in EC and cigarette use patterns between young people, but do not appear to influence longitudinal trajectories of EC and cigarette use within individuals.

IMPLICATIONS

This study examined within- and between-person associations between e-cigarette use, cigarette use, and shared risk factors (alcohol use, marijuana use, mental health symptoms) in a longitudinal cohort of youths. Within- and between-person analyses revealed reciprocal prospective associations between e-cigarette and cigarette use, suggesting a progression toward more frequent use of both products over time. The shared risk factors examined here did not affect escalations in e-cigarette or cigarette use over time within individuals, but likely influence which youths use these products. Findings add to a growing body of evidence suggesting that e-cigarette use increases subsequent cigarette use in young people.

The Vaping Epidemic in Adolescents

Electronic cigarette (e-cigarette) use has recently risen to the forefront of medical discussions across the country. A significant increase in e-cigarette use by adolescents has been observed over the last decade. This article discusses the targeting of adolescents by e-cigarette companies. It looks at how teenagers are uniquely affected by nicotine and at risk for progressing to using combustible cigarettes and marijuana. Lastly, it discusses the role of physicians in combating the spread of e-cigarettes.

Tobacco use in Lao People's Democratic Republic: Results from the 2015 National Adult Tobacco Survey

INTRODUCTION

Tobacco use is a burden for Lao People's Democratic Republic (Lao PDR). No published report has examined determinants of various tobacco uses to inform appropriate policies and prevention strategies. This paper reports tobacco uses by sociodemographic characteristics using data from the most recent Lao National Adult Tobacco Survey (NATS) in 2015.

METHODS

The NATS included a nationally representative sample of 7562 people aged ≥15 years, recruited through a stratified 2-stage cluster sampling approach in 18 provinces. All analyses were weighted. Multivariable logistic regression models were used to evaluate unadjusted and adjusted associations between variables of interest.

RESULTS

The NATS results showed that 32.4% of Lao people aged ≥15 years were current tobacco users (men: 51.2%, women: 15.4%). Cigarette smoking accounted for approximately 95% of all tobacco use in men, while tobacco chewing accounted for 60% of tobacco use in women. Current tobacco use was strongly associated with older ages and lower education levels (p<0.001). There were interactions between sex, education level, and income associated with tobacco use; specifically, women were more likely to have a lower education level and lower income than men, and these women were more likely to use tobacco.

CONCLUSIONS

Tobacco use prevalence in Lao PDR was among the highest in the region. There were variations in types and prevalence of tobacco use across sociodemographic subpopulations. The Lao government should continue current national tobacco control efforts and implement additional proven strategies to reduce tobacco use.

Vaping Expectancies: A Qualitative Study among Young Adult Nonusers, Smokers, Vapers, and Dual Users

BACKGROUND

"Expectancies," or beliefs about outcomes, robustly correlate with and predict several behaviors including electronic nicotine delivery system ("e-cigarette") use. However, there is limited qualitative research available regarding relevant e-cigarette vaping expectancies.

OBJECTIVES

The present study used a qualitative approach to derive and refine e-cigarette expectancy themes among young adults.

METHODS

We conducted 12 focus groups and two individual interviews with young adult nonusers, e-cigarette vapers, cigarette smokers, and dual users to assess beliefs about the effects of e-cigarettes. After a series of open-ended questions, follow-up questions assessed reactions to domains previously examined in expectancy measures for cigarette smoking and e-cigarette vaping. The constant comparative method was used to derive themes from transcripts.

RESULTS

Four main themes (Positive Reinforcement, Social Benefits, Negative Affect Reduction, Negative Consequences) emerged from the results. Each theme contained three associated subthemes (Positive Reinforcement: Sensorimotor Experiences, Taste, Stimulation; Social Benefits: Social Facilitation, Influence on Others, Convenience; Negative Affect Reduction: Stress Reduction, Appetite Reduction, Boredom Reduction; and Negative Consequences: Health Risks, Addiction, Secondhand Effects).

CONCLUSIONS/IMPORTANCE

Previously identified smoking expectancies appear relevant for young adult vaping, with some notable refinements. Positive reinforcement aspects encompassed aerosol clouds, vaping tricks, and unique flavors. Social benefits included influencing others via social media and competitive activity, as well as the convenience of use in a variety of places. Negative affect reduction was controversial among user groups, but vaping was seen as more interesting than smoking and thus more effective at boredom reduction. Young adults were uncertain regarding negative consequences, but appreciated a potential for secondhand effects. Measure refinement via qualitative research and future field testing can enhance our understanding of this relatively new behavior, supporting tobacco control surveillance, marketing/labeling regulations, and counter-advertising development/evaluation.

Electronic Cigarette Use and Attempts to Quit Smoking Cigarettes Among Adolescents in Taiwan

PURPOSE

This study assessed the relationship between electronic cigarette (e-cigarette) use and attempts to quit smoking cigarettes by adolescent smokers in Taiwan.

METHODS

Data were obtained from the cross-sectional Taiwan Global Youth Tobacco Survey conducted annually between 2014 and 2016, which included adolescents aged 12-18 years. The independent variable was e-cigarette use in the previous 30 days. The outcome variable was attempts to quit cigarette smoking during the previous 12 months. We controlled for the following variables: year of survey, gender, grade, monthly income/allowance, numbers of cigarettes per day, smoking status of parents and friends, use of other tobacco products, access to free tobacco products, assistance in quitting smoking, and exposure to anti-tobacco campaigns.

RESULTS

Among cigarettes smokers, the prevalence of current e-cigarette use (in the previous 30 days) increased from 9.82% (2014) to 27.46% (2016), whereas attempts to quit smoking cigarettes decreased slightly from 71.31% (2014) to 70.59% (2016). Current e-cigarette use (OR = 1.21) was positively associated with attempts to quit cigarette smoking. Smokers who observed anti-tobacco media messages (OR = 1.12), attended antismoking classes (OR = 1.17), were influenced by warnings on cigarette packages (OR = 3.32), or received help to quit (OR = 3.11) were more likely to have attempted to quit cigarettes.

CONCLUSIONS

We identified factors correlated with attempts to quit smoking, and recommend that the government continue monitoring electronic cigarette use, combat smoking in the media, provide antismoking classes, and expand health warnings on cigarette packages.

Youth who use e-cigarettes regularly: A qualitative study of behavior, attitudes, and familial norms

Limited research exists describing youth who use e-cigarettes on a regular basis, including knowledge of nicotine levels, health effects, and plans for future use. This qualitative study explored the patterns of use, social and familial norms, and perceptions of health effects among this group. Youth (N = 43), 14-17 years old, who described themselves as regular e-cigarette users, participated in 4 focus group discussions in Miami, Florida, and Raleigh, North Carolina in February 2016. Youth often initiated or continued e-cigarette use with a device obtained from a friend or family member, and often do not own their own device. They cite the flavors and doing tricks as the two main reasons they initially used e-cigarettes. Many reported that their family members are aware they use e-cigarettes, and that they have received implicit and explicit messages from family members that are positive toward ecigarette use. They are aware of the negative effects of nicotine, including addiction, but not confident that they are using e-liquids without nicotine. Participants reported they will stop using e-cigarettes when they become aware of reported negative health effects. Parents and family members are an important target audience for prevention campaigns and health messaging, given that their own use and acceptance could be encouraging initiation and continuation. Youth are using products containing nicotine and may be becoming addicted, even if they would not choose to use nicotine-containing e-juice. Increased awareness of negative health effects may encourage prevention and cessation of e-cigarette use among youth.

Bidirectional associations of e-cigarette, conventional cigarette and waterpipe experimentation among adolescents: A cross-lagged model

PURPOSE

With an increasingly diverse tobacco product market, it is imperative to understand the trajectories of product experimentation in order to design effective prevention programs. This study aims to explore the bidirectional associations of conventional cigarette, e-cigarette and waterpipe experimentation in a large adolescent sample.

METHODS

Longitudinal assessment of conventional cigarette, e-cigarette and waterpipe use initiation was conducted in a school-based cohort of 1369 9th graders (mean age=14.88 SD=0.48 at baseline) during fall 2014 and reassessed 6-months later using online self-reported questionnaires. Autoregressive cross-lagged analysis within structural equation modeling framework was performed to simultaneously estimate the initiation of these products over a six-month period, controlling for age, gender, and participation in an intervention program to reduce conventional cigarette initiation.

RESULTS

Tobacco product lifetime use was prevalent at baseline in the sample: conventional cigarettes (48.4%), e-cigarettes (35.8%), and waterpipe (20.8%). At six-month follow-up, trying conventional cigarettes predicted trying e-cigarette (adjusted odds ratio (AOR)=3.78, CI95%: 2.66-5.37) and trying waterpipe (AOR=2.82, CI95%: 2.00-3.97). Trying e-cigarette predicted trying conventional cigarette (AOR=3.57, CI95%: 1.96-6.49) and trying waterpipe (AOR=1.51, CI95%: 1.07-2.14). Although trying waterpipe predicted trying e-cigarette at follow-up (AOR=2.10, CI95%: 1.30-3.40), its use did not predict trying conventional cigarette (AOR=0.55, CI95%: 0.24-1.30).

CONCLUSIONS

The high rates of poly-tobacco use and the bidirectionality of tobacco product experimentation demands comprehensive tobacco control and prevention programs that address the increasingly diverse tobacco product market targeting adolescents.

Effects of nicotine-containing and "nicotine-free" e-cigarette refill liquids on intracranial self-stimulation in rats

BACKGROUND

Animal models are needed to inform FDA regulation of electronic cigarettes (ECs) because they avoid limitations associated with human studies. We previously reported that an EC refill liquid produced less aversive/anhedonic effects at a high nicotine dose than nicotine alone as measured by elevations in intracranial self-stimulation (ICSS) thresholds, which may reflect the presence of behaviorally active non-nicotine constituents (e.g., propylene glycol) in the EC liquids. The primary objective of this study was to assess the generality of our prior ICSS findings to two additional EC liquids. We also compared effects of "nicotine-free" varieties of these EC liquids on ICSS, as well as binding affinity and/or functional activity of nicotine alone, nicotine-containing EC liquids, and "nicotine-free" EC liquids at nicotinic acetylcholine receptors (nAChRs).

METHODS AND RESULTS

Nicotine alone and nicotine dose-equivalent concentrations of both nicotine-containing EC liquids produced similar lowering of ICSS thresholds at low to moderate nicotine doses, indicating similar reinforcement-enhancing effects. At high nicotine doses, nicotine alone elevated ICSS thresholds (a measure of anhedonia-like behavior) while the EC liquids did not. Nicotine-containing EC liquids did not differ from nicotine alone in terms of binding affinity or functional activity at nAChRs. "Nicotine-free" EC liquids did not affect ICSS, but bound with low affinity at some (e.g., α4ß2) nAChRs.

CONCLUSIONS

These findings suggest that non-nicotine constituents in these EC liquids do not contribute to their reinforcement-enhancing effects. However, they may attenuate nicotine's acute aversive/anhedonic and/or toxic effects, which may moderate the abuse liability and/or toxicity of ECs.

E-cigarettes: Impact of E-Liquid Components and Device Characteristics on Nicotine Exposure

BACKGROUND

Electronic cigarette (e-cigarette) use has increased substantially in recent years. While e-cigarettes have been proposed as a potentially effective smoking cessation tool, dualuse in smokers is common and e-cigarettes are widely used by non-smokers, including youth and young-adult non-smokers. Nicotine, the primary addictive component in cigarettes, is present at varying levels in many e-liquids. E-cigarettes may lead to initiation of nicotine use in adult and youth non-smokers, re-initiation of nicotine dependence in ex-smokers or increased severity of nicotine dependence in dual-users of cigarettes and e-cigarettes. As such, there are important clinical and policy implications to understanding factors impacting nicotine exposure from e-cigarettes. However, the broad and rapidly changing range of e-liquid constituents and e-cigarette hardware which could impact nicotine exposure presents a challenge. Recent changes in regulatory oversight of e-cigarettes underscore the importance of synthesizing current knowledge on common factors which may impact nicotine exposure.

METHODS

This review focuses on factors which may impact nicotine exposure by changing e-cigarette use behavior, puff topography, altering the nicotine yield (amount of nicotine exiting the e-cigarette mouth piece including nicotine exhaled as vapor) or more directly by altering nicotine absorption and bioavailability.

RESULTS

Topics reviewed include e-liquid components or characteristics including flavor additives (e.g., menthol), base e-liquid ingredients (propylene glycol, vegetable glycerin), components commonly used to dissolve flavorants (e.g., ethanol), and resulting properties of the e-liquid (e.g., pH), e-cigarette device characteristics (e.g., wattage, temperature, model) and user behavior (e.g., puff topography) which may impact nicotine exposure.

CONCLUSION

E-liquid characteristics and components, e-cigarette hardware and settings, and user behavior can all contribute substantially to nicotine exposure from e-cigarettes.

Gender Differences in U.S. Adolescent E-Cigarette Use

Purpose of Review

This study aims to review the recent (2012-2017) available gender difference data on e-cigarette use among adolescents.

Recent Findings

E-cigarettes are the most commonly used tobacco product among adolescents, and recent study findings showed that e-cigarette use can lead to cigarette smoking. However, gender differences in e-cigarette use among adolescents are relatively unknown.

Summary

We used the search terms "adolescents" and "e-cigarettes" on PubMed and identified 652 articles. Of these, 16 articles (2.5%) examined gender differences in adolescent e-cigarette use. Boys appear to have greater use of e-cigarettes, but girls may be at increased risk if e-cigarettes are targeted to them, as it has been for cigarettes. Data on gender differences are limited, and future research should continue to examine gender differences in e-cigarette use. Trends in use rates could evolve with new regulations and innovations in e-cigarette marketing and product features.